Neurons – nerve cells that transmit signals throughout the body – may not simply inherit their identity from the stem cells that produce them, according to a new study by researchers at the Stowers Institute for Medical Research.

The study, published in the Proceedings of the National Academy of Sciences, examined 232,251 cells during the development of the fruit fly's visual system. Researchers used the data to create a detailed map of how genes and regulatory regions change as neurons develop.

They found that many DNA regions linked to a neuron's identity were closed in its parent stem cell and became active only after the neuron completed its final division. This suggests that a neuron's identity is established during a short period immediately after it is born, rather than being simply inherited from its parent cell.

Researchers found that combinations of proteins called transcription factors control different sets of genes depending on the type of neuron. The same protein could also affect different genes in different neurons.

The findings could help researchers better understand how different types of neurons are produced. This may be relevant to efforts to replace neurons lost in conditions such as Parkinson's disease, ALS and glaucoma, although the study was conducted in fruit flies and does not establish a treatment for these diseases.

The researchers said the work also provides a framework for studying how disruptions in gene regulation during early development may contribute to neurological disorders.